Swine Flu: 5 Things You Need to Know About the Outbreak

Concern that the world could be on the brink of the first influenza pandemic in more than 40 years escalated Sunday as France, Hong Kong, New Zealand and Spain reported potential new cases in which people had been infected with swine flu and Canada confirmed several new cases. In the U.S., where 20 such infections have been confirmed, federal health officials declared a public-health emergency and are preparing to distribute to state and local agenciesa quarter of the country's 50 million-dose stockpile of antiviral drugs. Meanwhile, in hard-hit Mexico, where more than 80 people have died from what is believed to be swine flu, the government closed all public schools and canceled hundreds of public events in Mexico City.